1 /*
   2  * Copyright (c) 1998, 2014, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
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  23  */
  24 
  25 #ifndef SHARE_VM_UTILITIES_HISTOGRAM_HPP
  26 #define SHARE_VM_UTILITIES_HISTOGRAM_HPP
  27 
  28 #include "memory/allocation.hpp"
  29 #include "runtime/os.hpp"
  30 #include "utilities/growableArray.hpp"
  31 
  32 // This class provides a framework for collecting various statistics.
  33 // The current implementation is oriented towards counting invocations
  34 // of various types, but that can be easily changed.
  35 //
  36 // To use it, you need to declare a Histogram*, and a subtype of
  37 // HistogramElement:
  38 //
  39 //  HistogramElement* MyHistogram;
  40 //
  41 //  class MyHistogramElement : public HistogramElement {
  42 //    public:
  43 //      MyHistogramElement(char* name);
  44 //  };
  45 //
  46 //  MyHistogramElement::MyHistogramElement(char* elementName) {
  47 //    _name = elementName;
  48 //
  49 //    if(MyHistogram == NULL)
  50 //      MyHistogram = new Histogram("My Call Counts",100);
  51 //
  52 //    MyHistogram->add_element(this);
  53 //  }
  54 //
  55 //  #define MyCountWrapper(arg) static MyHistogramElement* e = new MyHistogramElement(arg); e->increment_count()
  56 //
  57 // This gives you a simple way to count invocations of specfic functions:
  58 //
  59 // void a_function_that_is_being_counted() {
  60 //   MyCountWrapper("FunctionName");
  61 //   ...
  62 // }
  63 //
  64 // To print the results, invoke print() on your Histogram*.
  65 
  66 #ifdef ASSERT
  67 
  68 class HistogramElement : public CHeapObj<mtInternal> {
  69  protected:
  70   jint _count;
  71   const char* _name;
  72 
  73  public:
  74   HistogramElement();
  75   virtual int count();
  76   virtual const char* name();
  77   virtual void increment_count();
  78   void print_on(outputStream* st) const;
  79   virtual int compare(HistogramElement* e1,HistogramElement* e2);
  80 };
  81 
  82 class Histogram : public CHeapObj<mtInternal> {
  83  protected:
  84   GrowableArray<HistogramElement*>* _elements;
  85   GrowableArray<HistogramElement*>* elements() { return _elements; }
  86   const char* _title;
  87   const char* title() { return _title; }
  88   static int sort_helper(HistogramElement** e1,HistogramElement** e2);
  89   virtual void print_header(outputStream* st);
  90   virtual void print_elements(outputStream* st);
  91 
  92  public:
  93   Histogram(const char* title,int estimatedSize);
  94   virtual void add_element(HistogramElement* element);
  95   void print_on(outputStream* st) const;
  96 };
  97 
  98 #endif
  99 
 100 #endif // SHARE_VM_UTILITIES_HISTOGRAM_HPP